//
// request_handler.cpp
// ~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2012 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#include "request_handler.hpp"
#include <fstream>
#include <sstream>
#include <string>
#include <boost/lexical_cast.hpp>
#include "mime_types.hpp"
#include "reply.hpp"
#include "request.hpp"

namespace http {
namespace server3 {

request_handler::request_handler(const std::string& doc_root)
  : doc_root_(doc_root)
{
}

void request_handler::handle_request(const request& req, reply& rep)
{
	// Decode url to path.
	std::string request_path;
	if (!url_decode(req.uri, request_path))
	{
		rep = reply::stock_reply(reply::bad_request);
		return;
	}

	// Request path must be absolute and not contain "..".
	if (request_path.empty() || request_path[0] != '/'
		|| request_path.find("..") != std::string::npos)
	{
		rep = reply::stock_reply(reply::bad_request);
		return;
	}

	// If path ends in slash (i.e. is a directory) then add "index.html".
	if (request_path[request_path.size() - 1] == '/')
	{
		request_path += "index.html";
	}

	// Determine the file extension.
	std::size_t last_slash_pos = request_path.find_last_of("/");
	std::size_t last_dot_pos = request_path.find_last_of(".");
	std::string extension;
	if (last_dot_pos != std::string::npos && last_dot_pos > last_slash_pos)
	{
		extension = request_path.substr(last_dot_pos + 1);
	}

	// Open the file to send back.
	std::string full_path = doc_root_ + request_path;
	if (server_cache.in_cache(full_path))
	{
		rep.content = server_cache.content_in_cache(full_path);
	}
	else
	{
		std::ifstream is(full_path.c_str(), std::ios::in | std::ios::binary);
		if (!is)
		{
			rep = reply::stock_reply(reply::not_found);
			return;
		}
		char buf[512];
		while (is.read(buf, sizeof(buf)).gcount() > 0)
			rep.content.append(buf, is.gcount());
		server_cache.update_cache(full_path, rep.content);
	}

	// Fill out the reply to be sent to the client.
	rep.status = reply::ok;
	rep.headers.resize(2);
	rep.headers[0].name = "Content-Length";
	rep.headers[0].value = boost::lexical_cast<std::string>(rep.content.size());
	rep.headers[1].name = "Content-Type";
	rep.headers[1].value = mime_types::extension_to_type(extension);
}

bool request_handler::url_decode(const std::string& in, std::string& out)
{
	out.clear();
	out.reserve(in.size());
	for (std::size_t i = 0; i < in.size(); ++i)
	{
		if (in[i] == '%')
		{
			if (i + 3 <= in.size())
			{
				int value = 0;
				std::istringstream is(in.substr(i + 1, 2));
				if (is >> std::hex >> value)
				{
					out += static_cast<char>(value);
					i += 2;
				}
				else
				{
					return false;
				}
			}
			else
			{
				return false;
			}
		}
		else if (in[i] == '+')
		{
			out += ' ';
		}
		else
		{
			out += in[i];
		}
	}
	return true;
}

} // namespace server3
} // namespace http
